Exam # 1 Chem 121.09 Winter 2012
Name ________________________________________________
Mark the following multiple choice questions with the one best answer from the given choices.
__A__1. The correct prefix for the multiplier 1000 is:
A) kilo B) milli C) micro D) nano E) none of the above
___C_2. Physical properties are:
A) those that a substance displays only through changing its composition.
B) those that cause atoms and molecules to change.
C) those that a substance displays without changing its composition.
D) identical for all solid matter.
E) none of the above
__C__3. In order, what is the freezing point, room temperature and boiling point of water in the Celsius scale?
A) 32-75-212 B) 0-75-100 C) 0-25-100 D) 0-298-373 E) none of the above
__C___4. Which of the following is a physical property of matter?
A. it does not burn
B. produces a gas when placed in an acid
C. freezes at -10oF
D. the surface turns black in air
___A__5. Which of the following terms correctly applies to a molecule of CO2?
A. triatomic, heteroatomic
B. polyatomic, diatomic
C. triatomic, homoatomic
D. diatomic, heteroatomic
___B__6. Which of the following numbers is correctly expressed using scientific notation?
A.) 3489 B) 5.248 X 104 C) 45.78 X 106 D) .0987 X 103
___B__7. Do the following calculation, and express the answer using correct scientific notation.
(2.97 X 102) X (6.09 X 10-7)
A). 5.53 X 103 B) 1.81 X 10-4 C) 4.88 X 108 D) 2.05 X 10-9
___B__8. Which number has the greatest number of significant digits?
A) 1.0035 B) 17.5000 C) 0.0000625 D) 6.022 X 1023
___D__9. Knowing that 1 g = 0.035 oz and 16 ounces = 1 lb, calculate the number of grams in 10 pounds.
A) 35 B) 0.56 C) 1.8 D) 4.6 X 103
___A__10. If urine has a density of 1.08 g/mL, what would be the mass of a 125 mL urine sample?
A) 135 g B) 0.00864 g C) 116 g D) 125 g
___C__11. Do the following calculation and express the answer using the correct number of significant figures.
(1.21 X 10-3 + 1.3 X 10-3) X 6.453 X 102 =
A) 1.619 B) 2 C) 1.6 D) 1.62
__B___12. Isotopes differ from each other in what way?
A) They have different numbers of protons in the nucleus.
B) They have different numbers of neutrons in the nucleus.
C) They have different numbers of electrons outside the nucleus.
D) More than one response is correct.
___D__13. Which of the following correctly describes subatomic particles?
1. Mass:
<
= n (to 3 significant figures)
2. Magnitude of charge: n <
3. Location: outside nucleus
A) 1 only
B) 2 only
C) 3 only
=
,
.
inside nucleus n
D) 1 and 2
E) 2 and 3
F) 1 and 3
___B__14. Consider the representation shown below.
This substance would be classified as:
A) an element containing 6 atoms.
B) a compound containing atoms of two elements.
C) a homogenous mixture of two elements.
D) a homogenous mixture of two compounds.
___B__15. A neutral isotope of an element contains 21 electrons and 24 neutrons. What is the symbolic
representation for this isotope?
A)
C)
B)
D)
___A__ 16. Given that the atomic weight of carbon is 12.01 grams, which of the following isotopes
would you expect to have the greatest natural abundance?
A) C-12 B) C-13 C) C-14 D) all are about equal in abundance E) none of the above
___B__ 17. The weight of an object is the same everywhere but the mass is dependent upon the force of gravity.
A) True B) False C) it depends upon the amount of mass
___C__18. How many total atoms are in the formula PbCl4?
A) 2 B) 4 C) 5 D) 8 E) none of these are correct
___D__19. Which of the following statements about the mole is FALSE?
A) The size of a mole of atoms has a reasonable mass.
B) A mole of a monatomic element corresponds to one Avogadro's number of atoms.
C) One mole of a monatomic element has a mass equal to its atomic mass expressed in grams.
D) One mole of water contains 1/2 mole of oxygen atoms.
20. Match all the characteristics that accurately describe each of the substances in the left hand column
Substance
AEF____HCl
C______air (in this room)
BEF____N2
_D______oil and vinegar
characteristic
A. Compound
B. Element
C. homogeneous mixture
D. heterogeneous mixture
E. Pure substance
F. diatomic
21. A beaker is marked into 10 mL units. If one measures the precise volume of about 20 mL of liquid, how many
significant figures should be reported?
Only 2 sig fig since one can measure to the nearest gradations (+/- 10) then estimate one more figure in
this case the 1’s position so a valid report would be something like 20. Or 19 or 21. Something with 2 sig figs
Show all your work for the following exercises.
22. Calculate the formula weight of SnO4.
1 Sn = 118.71 + 4 O X 16.00 (64.00) = 182.71 g
23. What is the number of g of oxygen in a 44.0 gram sample of carbon dioxide (CO2)?
44.0 g CO2 X 1 mol CO2/44.0 g X 2 mol O/1 mol CO2 X 16.00 g O/1 mol O = 32.0 grams O
24. How many hydrogen atoms are in 1.00 mole of NH3?
1.00 mol NH3 X 3 mol H/1 mol NH3 X 6.02 X 10^23 atoms/mol = 1.08 X 10^24 atoms of H